Revelation 10:2
And he had in his hand a little book open: and he set his right foot upon the sea, and his left foot on the earth, (Revelation 10:2)
In his hand.
 Compare the symbolism of Eze. 2:9.
A little book.
 Gr. biblaridion, “a little scroll.” In the NT biblaridion appears only in the present chapter. As contrasted with the scroll (biblion) in the hand of God in ch. 5:1, this little scroll is distinctly smaller. Compare the symbolism of Eze. 2:9.
Open.
 The Greek implies that the book has been opened and still is open. By contrast, the previous scroll was sealed with seven seals (ch. 5:1). Daniel had been instructed to “shut up the words, and seal the book, even to the time of the end” (ch. 12:4). This admonition applies particularly to the part of Daniel’s prophecies that deals with the last days (see on ch. 12:4), and doubtless especially to the time element of the 2300 days (ch. 8:14) as it relates to the preaching of the first, second, and third angels’ messages (Rev. 14:6-12). Inasmuch as the message of the present angel deals with time, and presumably with events at the time of the end, when the book of Daniel was to be unsealed (Dan. 12:4), it seems reasonable to conclude that the little book open in the hand of the angel was the book of Daniel. With the presentation to John of the little book open, the sealed portions of Daniel’s prophecy are revealed. The time element, pointing out the end of the 2300-day prophecy, is made clear. Consequently the present chapter focuses upon the time when the proclamation of vs. 6, 7 was made, that is, during the years 1840 to 1844 (see on v. 6; see EGW Supplementary Material on ch. 10:1-11).
Upon the sea … on the earth.
 Sea and earth are used repeatedly to designate the world as a whole (see Ex. 20:4, 11; Ps. 69:34). The fact that the angel stands upon both sea and earth implies the worldwide proclamation of his message, and also his power and authority over the world.